Bile acid synthesis promoter, composition for promoting bile acid synthesis and food composition for promoting bile acid synthesis

ABSTRACT

[Problem] To provide a novel medicine that is capable of promoting cholesterol metabolism to thereby treat, ameliorate or prevent various symptoms associated with increase in blood cholesterol level. [Solution] The present inventors newly found that arctigenin has an effect of promoting the conversion of cholesterol into bile acid. The present invention provides a bile acid synthesis promoter, a composition for promoting bile acid synthesis and a food composition for promoting bile acid synthesis each comprising arctigenin and/or arctiin as active ingredient(s).

TECHNICAL FIELD

The present invention relates to a bile acid synthesis promoter, acomposition for promoting bile acid synthesis and a food composition forpromoting bile acid synthesis which can promote the synthesis of bileacid from cholesterol in the liver.

BACKGROUND ART

Cholesterol is an important component concerning various physiologicalphenomena of the living body. However, an excess amount of cholesterolin the blood is known to cause lifestyle-related diseases such asarteriosclerosis. Cholesterol forms a complex with proteins in the bloodand exists as lipoprotein. Among this lipoprotein, low-densitylipoprotein cholesterol (LDL cholesterol) is said to promotearteriosclerosis. Therefore, it is considered that arteriosclerosis canbe ameliorated by reducing lipid in the blood, particularly LDLcholesterol.

Cholesterol is converted into bile acid in the liver and excreted fromthe bowel. The bile acid synthesis is a main mechanism to eliminateextra cholesterol outside the body. It is considered that varioussymptoms caused by increased blood cholesterol can be treated,ameliorated or prevented by promoting such conversion of cholesterolinto bile acid.

Cholesterol is converted into bile acid in the liver by bile acidsynthetic enzymes such as CYP7A1 and CYP8B1 (non-patent document 1).Bile acid is excreted partly after being secreted into the intestinaltract. The remaining bile acid is reabsorbed from the bowel and returnsto the liver. Bile acid is recycled by circulating between the liver andthe intestinal tract. The conversion of cholesterol into bile acid isregulated by bile acid which is reabsorbed and returned to the liver.Bile acid returned to the liver binds to FXR (farnesoid X receptor)which is a nuclear receptor and activate it. Activated FXR induces theexpression of SHP (small heterodimer partner) which is another nuclearreceptor. SHP has the action to inhibit the expression of bile acidsynthetic enzyme genes such as Cyp7a1 and Cyp8b1. In addition, FXRpromotes the expression of FGF15 (Fibroblast growth factor 15) in theintestinal tract. FGF15 inhibits the expression of Cyp7a1 and Cyp8b1which are bile acid synthetic enzyme genes by binding to receptor FGF4of the liver to activate it.

As a medicine to promote lipid metabolism, an agent for improving lipidmetabolism which include krill protein as an active ingredient isdisclosed, for example, in patent document 1. The agent for improvinglipid metabolism described in patent document 1 reduces bloodcholesterol by cholesterol absorption inhibition or bile acid excretioneffect.

CITATION LIST Patent Literature

Patent Literature 1:JP-A-2010-095456

Non-Patent Literature

Non-Patent Literature 1: Hepatology, 2012, Vol.56, No.3, p.1034-1043.

SUMMARY OF INVENTION Technical Problem

The present invention is intended to provide a novel medicine that iscapable of promoting cholesterol metabolism to thereby treat, ameliorateor prevent various symptoms associated with increase in bloodcholesterol level.

Solution to Problem

The present inventors found that the amount of bile acid was increasedin comparison with control group when measuring the amount of bile acidin feces of the leptin receptor-deficient model administered arctigenin.They also found that Cyp8b1, which is a bile acid synthetic enzyme, ispositively regulated and SHP, FXR and FGF4R of the liver, which have theaction to inhibit the bile acid synthesis, as well as small intestinalFGF15 and SHP are negatively regulated in arctigenin administrated group(AG group) in comparison with control group. That is, they newly foundthat arctigenin has an effect to promote conversion of cholesterol intobile acid, and they completed the present invention.

The present invention provides a bile acid synthesis promoter comprisingarctigenin and/or arctiin as an active ingredient(s).

The present invention also provides a composition for promoting bileacid synthesis comprising arctigenin and/or arctiin as an activeingredient(s).

The present invention also provides a composition for promoting bileacid synthesis comprising arctigenin and/or arctiin as burdock, burdockfruit, burdock sprout or Forsythia fruit or extracts thereof in theabove composition for promoting bile acid synthesis.

The present invention also provides a food composition for promotingbile acid synthesis comprising arctigenin and/or arctiin as an activeingredient(s).

The present invention also provides a food composition for promotingbile acid synthesis comprising arctigenin and/or arctiin as burdock,burdock fruit, burdock sprout or Forsythia fruit or extracts thereof inthe above food composition for promoting bile acid synthesis.

The present invention also provides an expression promoter of bile acidsynthetic enzymes comprising arctigenin and/or arctiin as an activeingredient(s).

The present invention also provides a bile acid excretion promotercomprising arctigenin and/or arctiin as an active ingredient(s).

The present invention also provides a cholesterol metabolism promoter inthe liver comprising arctigenin and/or arctiin as an activeingredient(s).

Advantageous Effects of Invention

Since the present invention has an action to promote the bile acidsynthesis, it can promote cholesterol metabolism to thereby treat,ameliorate or prevent various symptoms associated with increase in bloodcholesterol level.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 A graph showing the amount of bile acid in feces in control groupand AG group (μmol/L).

FIG. 2 A graph showing the amount of total cholesterol (mg/dL) in theliver in control group and AG group.

FIG. 3 A graph showing the relative mRNA expression of Cyp8b1, SHP, FXRand FGF4R of the liver in control group and AG group.

FIG. 4 A graph showing the relative mRNA expression of small intestinalFGF15 and SHP in control group and AG group.

DESCRIPTION OF EMBODIMENTS

The present invention provides a bile acid synthesis promoter and acomposition for promoting bile acid synthesis comprising arctigeninand/or arctiin as an active ingredient(s).

Bile acid is a generic term of steroid derivatives having a cholanicacid backbone synthesized from cholesterol in the liver. In the presentinvention, bile acid comprises, for example, unbound bile acid such ascholic acid, chenodeoxycholic acid, deoxycholic acid and lithocholicacid; binding bile acid such as taurocholic acid, glycocholic acid,glycochenodeoxycholic acid, taurochenodeoxycholic acid, glycodeoxycholicacid, taurodeoxycholic acid, glycolithocholic acid and taurolithocholicacid, and salts and conjugates thereof. In addition, bile acid in thepresent invention includes various kinds of bile acid found in bile ofmammals, birds, reptiles, amphibians, fishes and the like as well asbile acid found in humans.

The “synthesis of bile acid” as used herein refers to synthesis,conversion or metabolism of cholesterol into bile acid in the liver. “Topromote the bile acid synthesis” as used herein includes initiating,quickening, accelerating and increasing the synthesis of bile acid.Promoting the bile acid synthesis can be determined by increase of theamount of bile acid in the liver, decrease of cholesterol in the liver,increase of the amount of bile acid in feces, increase of the expressionof bile acid synthetic enzymes and the like.

The bile acid synthesis promoter and the composition for promoting bileacid synthesis of the present invention comprise arctigenin and/orarctiin as an active ingredient(s). Arctigenin and arctiin are one ofdiphenylpropanoid (lignans) included in plants such as burdock. It isknown that arctiin is a precursor of arctigenin and is metabolized invivo to become arctigenin. As arctigenin and/or arctiin, chemicallysynthesized arctigenin and/or arctiin may be used, and arctigenin and/orarctiin isolated from plants may be used. In addition, as arctigeninand/or arctiin, a plant itself including arctigenin and/or arctiin or anextract of this plant may be used. Plants including arctigenin and/orarctiin comprise, for example, Arcticum lappa (burdock) (sprout, leaf,rhizome, burdock fruit), Forsythia x intermedia (flower, leaf, fruit,rhizome), Forsythia viridissima var. koreana (flower, leaf, fruit,rhizome), Forsythia suspense (Forsythia fruit) (flower, leaf, fruit,rhizome), Forsythia viridissima (flower, leaf, fruit, rhizome).Carthamus tinctorius, Centaurea cyanus, Cirsium vulgare, Centaureabenedicta (Cnicus benedictus), Cynara cardunculus, Onopordum acanthium ,thistle (Aniurokoazami), Sesamum indicum, Ipomoea cairica, Polygalachinensis, Trachelospermum asiaticum var. glabrum, Trachelospermumasiaticum, Trachelospermum gracilipes var. liukiuense, Trachelospermurngracilipes, Trachelospermum jasminoides, Trachelospermum jasminoidesvar. pubescens, Wikstroemia indica, Persicaria orientalis, Cerasusjamasakura, Arabidopsis thaliana, amaranth, Jugians (walnut), Avenasat/va (oat), Triticum spelta, soft wheat, Cupressus lusitanica andTorreya nucifera. Above all, burdock (particularly burdock fruit andburdock sprout) and Forsythia fruit (particularly leaf) are preferablebecause they have high content of arctigenin and/or arctiin. When usinga plant itself, the plant which is raw or dried and chopped or is driedand powdered can be used.

When using an extract of a plant as arctigenin and/or arctiin, theextract may be prepared from the plant, for example, by followingmethod. The extract as used in the present invention may be extracted,for example, from a plant including arctigenin and/or arctiin by twosteps of an enzymatic conversion step and an extraction step using anorganic solvent.

The enzymatic conversion step is a step enzymically converting arctiinincluded in the plant into arctigenin by β-glucosidase, which is anendogenous enzyme in the plant. Specifically, the plant which was driedand cut is kept at an appropriate temperature to make endogenousβ-glucosidase act and advance the reaction from arctiin to arctigenin,For example, the plant can be kept at a certain temperature by addingany solution such as water to the cut plant and stirring them at atemperature of around 30° C. (20 to 50) and the like.

The extraction step using an organic solvent is a step to extractarctigenin and arctiin from a plant using any appropriate organicsolvent. That is, it is a step to extract an extract (extract) from aplant by adding an appropriate solvent in the condition that arctigeninbecame the high content through the enzymatic conversion step describedabove. For example, an appropriate solvent is added to the plant andthen heated and stirred for an appropriate period of time, and anextract is extracted. Furthermore, the extract can be extracted usingany extraction method well known to those skilled in the art, such asheating to reflux, drip extraction, immersion extraction or thepressurized extraction, instead of heating and stirring.

Because arctigenin is water-insoluble, the yield of arctigenin can beimproved by adding an organic solvent. As the organic solvent, anyorganic solvent can be used. For example, alcohol such as methanol,ethanol and propanol, and acetone can be used. Considering from a safetystandpoint, it is preferable to use 30% ethanol as the organic solvent.When the solvent is evaporated from the extract, a paste-likeconcentrate is obtained and a dried product can be obtained by furtherdrying the concentrate.

The bile acid synthesis promoter and the composition for promoting bileacid synthesis of the present invention can be pharmaceuticalpreparations in any form. The bile acid synthesis promoter and thecomposition for promoting bile acid synthesis can be, as oraladministration pharmaceutical preparations, for example, tablet such asdragee, buccal tablet, coat tablet and chewable tablet; troche; pill;powdered drug; capsule including hard capsule and soft capsule; granule;and liquid such as suspension, emulsion, syrup, elixir and the like.

In addition, the bile acid synthesis promoter and the composition forpromoting bile acid synthesis of the present invention can bepharmaceutical preparations for parenteral administration such asintravenous injection, subcutaneous injection, intraperitonealinjection, intramuscular injection, transdermal administration, nasaladministration, transpulmonary administration, enteral administration,buccal administration and transmucosal administration. For example, thebile acid synthesis promoter and the composition for promoting bile acidsynthesis of the present invention can be injection, transdermalabsorption tape, aerosol, suppository and the like.

The bile acid synthesis promoter and the composition for promoting bileacid synthesis of the present invention can also be provided as theexternal preparation. The external preparation of the present inventioncan be pharmaceuticals, cosmetics and the like. The external preparationof the present invention can be an external preparation to apply toskin, scalp, hair, mucous membrane, nail and the like. The externalpreparation includes, for example, liniments such as creams, ointments,liquids, gels, lotions, emulsions, aerosols, sticks, seat masks, solids,foams, oils and hard gel sticks; patches such as cataplasms, plasters,tapes and patches; sprays and the like.

The bile acid synthesis promoter and the composition for promoting bileacid synthesis of the present invention can also be in a form suitablefor foods and may be, for example, solid form, liquid form, granularform, grainy form, powder form, capsule form, creamy form, paste formand the like.

The composition for promoting bile acid synthesis of the presentinvention can be a composition used for pharmaceuticals, cosmetics,foods and the like. The composition for promoting bile acid synthesis ofthe present invention can further include any components commonly usedfor pharmaceuticals, cosmetics and foods. For example, the compositionfor promoting bile acid synthesis of the present invention may furtherinclude a base, a carrier, a excipient, a binder, a disintegratingagent, a lubricant, a coloring agent and the like which arepharmaceutically acceptable.

Examples of the carrier and the excipient used for the composition forpromoting bile acid synthesis include lactose, glucose, white softsugar, mannitol, dextrin, potato starch, corn starch, calcium carbonate,calcium phosphate, calcium sulfate, crystalline cellulose and the like.

Examples of the binder include starch, gelatin, syrup, tragacanth gum,polyvinyl alcohol, polyvinyl ether, polyvinylpyrrolidone,hydroxypropylcellulose, methylcellulose, ethylcellulose,carboxymethylcellulose and the like.

Examples of the disintegrating agent include starch, agar, gelatinpowder, crystalline cellulose, calcium carbonate, sodium hydrogencarbonate, sodium alginate, sodium carboxymethylcellulose, calciumcarboxymethylcellulose and the like.

Examples of the lubricant include magnesium stearate, hydrogenatedvegetable oil, talc, macrogol and the like, As the coloring agent, anycoloring agent which has been accepted to be added to pharmaceuticals,cosmetics and foods can be used.

In addition, the composition for promoting bile acid synthesis, ifrequired, may be coated with one or more layers of white soft sugar,gelatin, refined shellac, gelatin, glycerin, sorbitol, ethylcellulose,hydroxypropylcellulose, hydroxypropylmethylcellulose,polyvinylpyrrolidone, cellulose acetate phthalate,hydroxypropylmethylcellulose phthalate, methyl methacrylate, methacrylicacid polymer and the like.

Moreover, if required, a pH-controller, a buffering agent, a stabilizer,a preservative, an antiseptic, a diluent, a coating agent, a sweetener,an aroma, a solubilizing agent and the like may be added to thecomposition for promoting bile acid synthesis.

The present invention also provides pharmaceuticals comprising thecomposition for promoting bile acid synthesis of the present invention.Pharmaceuticals of the present invention can be pharmaceuticals topromote the synthesis of cholesterol into bile acid. Pharmaceuticals ofthe present invention can also be pharmaceuticals to treat, ameliorateand prevent various kinds of symptoms associated with increase in bloodcholesterol level, and for example, it can be pharmaceuticals to treat,ameliorate and prevent dyslipidemia, arteriosclerosis, angina,myocardial infarction, stroke, cerebral infarction and cerebralhemorrhage.

The present invention also provides a food composition for promotingbile acid synthesis comprising arctigenin and/or arctiin as an activeingredient(s). The food composition for promoting bile acid synthesis ofthe present invention can be composed in a manner similar to those ofthe bile acid synthesis promoter and the composition for promoting bileacid synthesis described above. The food composition of the presentinvention can be a food composition for ameliorating or preventingdiseases such as dyslipidemia, arteriosclerosis, angina, myocardialinfarction, stroke, cerebral infarction and cerebral hemorrhage andconditions thereof.

The “food composition” as used herein includes foods for the ill, healthfoods, functional foods, foods for specified health use, dietarysupplements, supplements and the like as well as general foods anddrinks. Examples of the general foods and drinks include various drinks,various foods, processed foods, liquid foods (soups and the like),seasonings, nutrition-supplement drinks, snacks and the like. The“processed foods” as used herein mean foods obtained by processingand/or cooking natural foodstuffs (animals and plants, and the like) andinclude, for example, processed meat, processed vegetables, processedfruits, frozen foods, retort-pouched foods, canned foods, bottled foods,instant foods and the like. The food composition of the presentinvention may be a food with an indication saying that the bile acidsynthesis is promoted or the cholesterol metabolism is promoted. Thefood composition of the present invention may also be provided in a formcontained in a bag, a container and the like. The bag and the containerused in the present invention can be any bag and any container which aregenerally used for foods.

The content of arctigenin and/or arctiin in the bile acid synthesispromoter, the composition for promoting bile acid synthesis and the foodcomposition for promoting bile acid synthesis of the present inventionshould be the amount that an effect to promote the bile acid synthesiscan be exerted and can be set depending on subjects to apply, purposesand administration methods (intake methods) appropriately. For example,when making humans ingest, preferably, arctigenin and/or arctiin can beincluded so that an intake per day becomes 10 to 2000 mg.

The present invention also provides the expression promoter of bile acidsynthetic enzymes which contains arctigenin and/or arctiin as an activeingredient(s). The bile acid synthetic enzymes include, for example,CYP7A1, CYP8B1 and the like. Arctigenin has the action to promote theexpression of bile acid synthetic enzymes as shown in examples describedbelow. Arctigenin also has the action to inhibit the expression ofvarious kinds of factors such as SHP, FXR, FGF4R and FGF15 with actionto negatively regulate the expression of bile acid synthetic enzymes.

“To promote the expression” of gene as used herein means, for example,to increase the amount of transcription products derived from genes, toincrease the amount of proteins derived from genes and the like. Inaddition, “to inhibit the expression” as used herein means, for example,to decrease the amount of transcription products derived from genes andto decrease the amount of proteins derived from genes.

The expression promoter of bile acid synthetic enzymes of the presentinvention may contain arctigenin and/or arctiin as burdock, burdockfruit, burdock sprout or Forsythia fruit or extracts thereof. Theexpression promoter of bile acid synthetic enzymes of the presentinvention can also be composed in manners similar to those of the bileacid synthesis promoter, the composition for promoting bile acidsynthesis and the food composition for promoting bile acid synthesis ofthe present invention described above.

The expression promoter of bile acid synthetic enzymes of the presentinvention can promote the synthesis of cholesterol into bile acid bypromoting the expression of bile acid synthetic enzymes. Therefore, theexpression promoter of bile acid synthetic enzymes of the presentinvention can improve the cholesterol metabolism to thereby treat,ameliorate or prevent various symptoms associated with increase in bloodcholesterol level.

The present invention also provides the bile acid excretion promoterwhich contains arctigenin and/or arctiin as an active ingredient(s). The“bile acid excretion” as used herein refers to excretion to the outsidethe body of bile acid and refers to, for example, excreting bile acid infeces from intestinal tract.

The bile acid excretion promoter of the present invention may containarctigenin and/or arctiin as burdock, burdock fruit, burdock sprout orForsythia fruit or extracts thereof. The bile acid excretion promoter ofthe present invention can also be composed in manners similar to thoseof the bile acid synthesis promoter, the composition for promoting bileacid synthesis and the food composition for promoting bile acidsynthesis of the present invention. The bile acid excretion promoter ofthe present invention can improve cholesterol metabolism to therebytreat, ameliorate or prevent various symptoms associated with increasein blood cholesterol level.

The present invention also provides the cholesterol metabolism promoterin the liver which contains arctigenin and/or arctiin as an activeingredient(s). The “cholesterol metabolism” as used herein refers toconverting cholesterol into another compound, for example, convertingcholesterol into bile acid.

The cholesterol metabolism promoter in the liver of the presentinvention may contain arctigenin and/or arctiin as burdock, burdockfruit, burdock sprout or Forsythia fruit or extracts thereof. Thecholesterol metabolism promoter in the liver of the present inventioncan also be composed in manners similar to those of the bile acidsynthesis promoter, the composition for promoting bile acid synthesisand the food composition for promoting bile acid synthesis of thepresent invention. The cholesterol metabolism promoter in the liver ofthe present invention can improve cholesterol metabolism to therebytreat, ameliorate or prevent various symptoms associated with increasein blood cholesterol level.

EXAMPLES

Examples are shown below and the embodiments of the present inventionare explained further in detail, however the present invention is notlimited to the following examples.

Measurement of Enzymatic Activity

The β-glucosidase activities of burdock fruit were measured by thefollowing method. Burdock fruit samples of different origins anddifferent lots were pulverized with a Wiley mill, and the pulverizedburdock fruit samples each in an amount of 0.1 g were diluted with 10 mLof water. Sample solutions were thus obtained.

As the substrate solution, 20 mmol/L p-nitrophenyl-β-D-glucopyranosideaqueous solution was prepared by adding water to 0.15 g ofp-nitrophenyl-β-D-glucopyranoside and obtain the constant volume of 25mL. 0.5 mL of 20 mmol/L p-nitrophenyl-β-D-glucopyranoside aqueoussolution was added to 1 mL of 0.1 mol/L acetic acid buffer, and areaction mixture was thus prepared, and then preheated at 37° C. forapproximately five minutes.

After adding 0.5 mL of sample solution to the reaction mixture andadvancing the reaction at 37° C. for 15 minutes, the reaction wasstopped by adding 2 mL of 0.2 mol/L sodium carbonate aqueous solution,which is a solution to stop the reaction. The absorbance of this liquidat 400 nm was measured, and the enzymatic activity was determined usingthe following equation from the variation from the value of the blanksolution which was not subjected to the enzymatic reaction.

Enzymatic activity (U/g)=(absorbance of sample solution−absorbance ofblank solution)×4 mL×1/18.1 (millimolar molecular extinction coefficientof p-nitrophenol under the above measurement conditions:cm²/μmol)×1/optical path length (cm)×1/reaction period (minute)×1/0.5mL×1/concentration of sample solution (g/mL).

Example 1 Production of Burdock Fruit Extract 1

As an example of the composition for promoting bile acid synthesis ofthe present invention, an extract (extract) was extracted from burdockfruit. After cutting burdock fruit (enzymatic activity of 8.23 U/g), thepieces which completely passed through a sieve of 9.5 mm were furtherpassed through a sieve of 0.85 mm, and it was confirmed that 75% thereofremained. To 560 L of water which was kept at 29 to 33° C., 80 kg of thecut burdock fruit pieces were added, and the mixture was stirred for 30minutes. Then, 265 L of ethanol was added, and the solution was heatedto 85° C. and refluxed by heating for 60 minutes. This solution wascentrifuged, and a liquid burdock fruit extract was obtained. Thisoperation was repeated twice, and the obtained liquid extracts werecombined and concentrated under reduced pressure. Dextrin was added at25% to the solid contents of the extract, and the mixture was spraydried. The arctigenin and arctiin content were 6.2% and 7.1%,respectively, and burdock fruit extract powder (comprising 20% dextrin)with arctigenin/arctiin (weight ratio)=0.89 was thus obtained.

Example 2 Production of Burdock Fruit Extract 2

As an example of the composition for promoting bile acid synthesis ofthe present invention, an extract (extract) was extracted from burdockfruit. After cutting burdock fruit (enzymatic activity of 8.23 U/g), andthe pieces which completely passed through a sieve of 9.5 mm werefurther passed through a sieve of 0.85 mm, and it was confirmed that 75%thereof remained. To 560 L of water which was kept at 30 to 33° C., 80kg of the cut burdock fruit pieces were added, and the mixture wasstirred for 30 minutes. Then, 265 L of ethanol was added, and thesolution was heated to 85° C. and refluxed by heating for 30 minutes.The solution was centrifuged, and a liquid burdock fruit extract wasobtained. This operation was repeated twice, and the obtained liquidextracts were combined and concentrated under reduced pressure. Dextrinwas added at 25% to the solid contents of the extract, and the mixturewas spray dried. The arctigenin and arctiin content were 6.0% and 6.8%,respectively, and burdock fruit extract powder (comprising 20% dextrin)with arctigenin/arctiin (weight ratio)=0.87 was thus obtained.

Example 3 Production of Burdock Fruit Extract 3

As an example of the composition for promoting bile acid synthesis ofthe present invention, extract (extract) was extracted from burdockfruit. After cutting burdock fruit (enzymatic activity 7.82 U/g), thepieces which completely passed through a sieve of 9.5 mm were furtherpassed through a sieve of 0.85 mm, and it was confirmed that 75% thereofremained. To 560 L of water which was kept at 30 to 32° C., 80 kg of thecut burdock fruit pieces were added, and the mixture was stirred for 40minutes. Then, 258 L of ethanol was added after 60 minutes, and thesolution was heated to 85° C. and refluxed by heating for 30 minutes,The liquid was centrifuged, and a liquid burdock fruit extract wasobtained. This operation was repeated twice, and the obtained liquidextracts were combined and concentrated under reduced pressure, Dextrinwas added at 25% to the solid contents of the extract, and the mixturewas spray dried. The arctigenin and arctiin contents were 6.2% and 6.7%,respectively, and burdock fruit extract powder (comprising 20% dextrin)with arctigenin/arctiin (weight ratio)=0.93 was thus obtained.

Example 4 Production of Burdock Fruit Extract 4

As an example of the composition for promoting bile acid synthesis ofthe present invention, extract (extract) was extracted from burdockfruit. After cutting burdock fruit (enzymatic activity of 7.82 U/g), thepieces which completely passed through a sieve of 9.5 mm were furtherpassed through a sieve of 0.85 mm, and it was confirmed that 75% thereofremained. To 560 L of water which was kept at 30 to 32° C., 80 kg of thecut burdock fruit pieces were added, and the mixture was stirred for 30minutes. Then, 253 L of ethanol was added, and the solution was heatedto 85° C. and refluxed by heating for 40 minutes. The liquid wascentrifuged, and the obtained liquid extract was obtained. Thisoperation was repeated twice, and the obtained liquid extracts werecombined and concentrated under reduced pressure. Dextrin was added at25% to the solid contents of the extract, and the mixture was spraydried. The arctigenin and arctiin contents were 6.4% and 7.2%,respectively, and burdock fruit extract powder (comprising 20% dextrin)with arctigenin/arctiin (weight ratio)=0.89 was thus obtained,

Example 5 Production of Forsythia viridissima Leaf Extract 1

As an example of the composition for promoting bile acid synthesis ofthe present invention, extract (extract) was extracted from Forsythiaviridissima leaves. To 50 g of finely cut forsythia leaves comprising2.53% arctiin and 0.76% arctigenin, 350 mL of water was added, and themixture was kept at 37° C. for 30 minutes. Then, 150 mL of ethanol wasadded, and extraction with heating was conducted for 30 minutes. Thesolution was subjected to solid-liquid separation using a 100-mesh sieveand then to freeze drying, and 18.62 g of a Forsythia viridissima leafextract having an arctigenin content of 5.62% was thus obtained.

Example 6 Production of Forsythia viridissima Leaf Extract 2

As an example of the composition for promoting bile acid synthesis ofthe present invention, extract (extract) was extracted from Forsythiaviridissima leaves. To 720 g of finely cut Forsythia leaves comprising7.38% arctiin and 0.78% arctigenin, 5 L of water was added, and themixture was kept at 37° C. for 30 minutes. Then, 2.16 L of ethanol wasadded, and extraction with heating was conducted for 30 minutes. Thesolution was subjected to solid-liquid separation using a 100-mesh sieveand then to freeze drying, and 343.07 g of a Forsythia viridissima leafextract having an arctigenin content of 9.55% was thus obtained.

Example 7 Granules Containing Burdock Fruit Extract Powder

As an example of the composition for promoting bile acid synthesis ofthe present invention, granules were manufactured using a burdock fruitextract. The granules were manufactured according to the “JapanesePharmacopoeia”, General Rules for Preparations, section Granules. Thatis, the following components (1) to (3) were prepared and processed intogranules. The granules were divided into 1.5 g portions and packed in analuminum laminated film, and granules comprising 0.5 g of burdock fruitextract powder per one pack were obtained.

(1) Burdock fruit extract powder 33.3% of Example 2 (2) Lactose 65.2%(3) Hydroxypropylcellulose  1.5% Total  100%

Example 8 Granules Containing Burdock Fruit Extract Powder

As an example of the composition for promoting bile acid synthesis ofthe present invention, granules were manufactured using a burdock fruitextract. The granules were manufactured according to the “JapanesePharmacopoeia”, General Rules for Preparations, section Granules. Thatis, the following components (1) to (3) were prepared and processed intogranules. The granules were divided into 3.0 g portions and packed in analuminum laminated film, and granules comprising 2 g of burdock fruitextract powder per one pack were obtained.

(1) Burdock fruit extract powder 66.7% of Example 2 (2) Lactose 30.3%(3) Hydroxypropylcellulose  3.0% Total  100%

Example 9 Tablets Containing Burdock Fruit Extract Powder

As an example of the composition for promoting bile acid synthesis ofthe present invention, tablets were manufactured using a burdock fruitextract. The tablets were manufactured according to the “JapanesePharmacopoeia”, General Rules for Preparations, section Tablets. Thatis, the following components (1) to (6) were prepared, and the tabletswere obtained.

(1) Burdock fruit extract powder 37.0% of Example 2 (2) Crystallinecellulose 45.1% (3) Carmellose calcium 10.0% (4) Crospovidone  3.5% (5)Hydrated silicon dioxide  3.4% (6) Magnesium stearate  1.0% Total  100%

Example 10 Effect of Arctigenin on Bile Acid Synthesis

Laboratory Animals

Using 5-week-old male db/db mice (BKS.Cg-+Leprdb/+Leprdb/Jcl, purchasedfrom CLEA Japan, Inc.) that were leptin receptor-deficient model, theexperiments were started after one-week preliminary rearing. The animalswere reared under the environment of 23.0±5° C. of temperature, 50.0±10%of humidity and 12 hours of light-dark cycle. The animal experimentswere approved by animal care and use committee of Keio University andcarried out based on animal experiment rules of Keio University.

Experimental Method

After preliminary rearing, mice were divided into two groups of (a)control group and (b) arctigenin administrated group (AG group) (eachgroup n=8), and made AG group intake purified diet combined witharctigenin (>98.0%) 0.2% and purified diet (AIN-93G) for control groupfreely for nine weeks. After administration, 18-hour fasting wasperformed, and blood specimens were collected from abdominal vena cavaunder anesthesia, and the liver and the small intestine were sampled.

Measurement of the Amount of Bile Acid in Feces

Feces were collected from the rearing cage of each group at the end ofthe administration period, and the amount of bile acid in feces wasmeasured. 10 mg of dry powder of pooled feces was suspended in 0.2 mL of90% ethanol and incubated at 65° C. for 1 hour, and the supernatantafter centrifugation and the washing of the precipitates were collectedtogether. After evaporating the solvent to dryness, 0.5 mL of 90%ethanol was added to the residue and dissolved, and thus a sample forthe measurement was obtained. Ultra-performance liquid chromatographytandem mass spectrometry (UPLC-MS/MS, made by Waters) was used for themeasurement. FIG. 1 is a graph showing the amount of bile acid in feces(μmol/L) in control group and AG group. In AG group, there was largeamount of total bile acid in feces in comparison with control group.

Measurement of Total Cholesterol in Liver

Homogenate the liver obtained from each group and extracted total lipidusing a lipid extraction kit (Lipid Extraction Kit (Chloroform-Free),Cell Biolabs, Inc.). A total cholesterol level was measured from lipidextract using cholesterol E-test Wako (Wako Pure Chemical Corporation).FIG. 2 is a graph showing the amount of total cholesterol in the liver(mg/dL) in control group and AG group. In AG group, there was littleamount of total cholesterol in the liver than control group.

Expression Level of Liver Cholesterol Metabolism-Related Genes

After having performed extraction of total RNA from the obtained organsand cDNA synthesis on each group, the expression level of Cyp8b1, SHP,FXR and FGF4R of the liver which are the liver cholesterolmetabolism-related genes and small intestinal FGF15 and SHP werecompared by qPCR. As control, 18S rRNA was used. As the primer for qPCR,18S (F: TTCTGGCCAACGGTCTAGACAAC (SEQ ID NO: 1), R: CCAGTGGTCTTGGTGTGCTGA(SEQ ID NO: 2)), Cyp8b1 (F: GGAAGCCAAGAAGTCGTTCA (SEQ ID NO: 3), R:GACGCAGACTCTCCTCCATC (SEQ ID NO: 4)), SHP (F: CAAGGAGTATGCGTACCTGAAG(SEQ ID NO: 5), R: GGCTCCAAGACTTCACACAGT (SEQ ID NO: 6)), FXR(F:CAAAATGACTCAGGAGGAGTACG (SEQ ID NO: 7), R: GCCTCTCTGTCCTTGATGTATTG(SEQ ID NO: 8)), FGF4R (F:GAGGCATGCAGTATCTGG (SEQ ID NO: 9), R:CAAAGTCAGCGATCTTCATCACA (SEQ ID NO: 10)), FGF15(F: CCAGTGGTCTTGGTGTGCTGA(SEQ ID NO: 11), R: GGCCTGGATGAAGATGATATGGA (SEQ ID NO: 12)) were used.

FIG. 3 shows relative mRNA expression level of Cyp8b1, SHP, FXR andFGF4R of the liver in control group and AG group. The value in FIG. 3represents means of six mouse±standard errors (Mean±S.E.M). As a resultof Student's t-test, “*” is given when the p value was smaller than0.05, and “**” was given when the p value was smaller than 0.01. In AGgroup, in comparison with control group, expression level of Cyp8b1 wassignificantly high and expression level of SHP, FXR and FGF4R wassignificantly low.

FIG. 4 shows relative mRNA expression level of small intestinal FGF15and SHP in control group and AG group. In AG group, in comparison withcontrol group, expression level of small intestinal FGF15 and SHP waslow.

From these results, it was shown that arctigenin inhibits the expressionof SHP, FXR and FGF4R of the liver and small intestinal FGF15 and SHPwhile promoting the expression of Cyp8b1 of the liver. Therefore, it wasstrongly suggested that arctigenin promote the cholesterol metabolism inthe liver and has the action to promote the synthesis and the excretionof bile acid.

INDUSTRIAL APPLICABILITY

Since the present invention can promote metabolism of cholesterol bypromoting bile acid synthesis, it can preferably be used forpharmaceuticals, foods and the like to treat, ameliorate or preventvarious kinds of symptoms associated with the cholesterol increase.

Sequence Listing Free Text

1. A bile acid synthesis promoter comprising arctigenin and/or arctiinas an active ingredient(s).
 2. A composition for promoting bile acidsynthesis comprising arctigenin and/or arctiin as an activeingredient(s).
 3. A composition for promoting bile acid synthesisaccording to claim 2 comprising said arctigenin and/or arctiin asburdock, burdock fruit, burdock sprout or Forsythia fruit or extractsthereof.
 4. A food composition for promoting bile acid synthesiscomprising arctigenin and/or arctiin as an active ingredient(s).
 5. Afood composition for promoting bile acid synthesis according to claim 4comprising said arctigenin and/or arctiin as burdock, burdock fruit,burdock sprout or Forsythia fruit or extracts thereof.
 6. An expressionpromoter of bile acid synthetic enzymes comprising arctigenin and/orarctiin as an active ingredient(s).
 7. A bile acid excretion promotercomprising arctigenin and/or arctiin as an active ingredient(s).
 8. Acholesterol metabolism promoter in the liver comprising arctigeninand/or arctiin as active ingredient(s).